At present, the great development of communications technology accelerates the upgrading of the communications network; the security of the network, however, is the most fundamental performance criteria. For example, for the voice service, the switching time for end-to-end protection must be within 200 ms to meet the performance criteria. In order to meet various performance criteria, the IP bearer network brings into the device, path, network, etc Multi-Protocol Label Switching, Traffic Engineering (MPLS TE) protection technology.
The MPLS TE technology refers to the combination of MPLS and Resource Reservation Protocol (RSVP) TE technologies, which performs the end-to-end resource reservation by establishing specified a Label Switch Path (LSP); when a congestion occurs in an IP backbone networks (a local traffic congestion may be for network resource insufficiency or imbalance), the traffic may bypass the congestion node to realize the balance of the network traffic. When resources are limited, the MPLS TE may preempt the LSP bandwidth of low priority to meet the requirement of high bandwidth LSP or important service.
Meanwhile, when a congestion occurs in a path on the LSP or at a node of the network, the MPLS TE may quickly switch the traffic to the standby path through the Fast Reroute (FRR), where FRR in the MPLS TE (TE FRR) is a technology for realizing local network congestion protection of the network; the TE FRR ensures that the traffic may be quickly switched to the standby path when passing the congestion of the path or node; the speed of the TE FRR switching may be less than 50 ms, which can reduce the traffic data loss caused by the network congestion to a great extent.
On the basis of the RSVP-TE signaling protocol, the fault of the path and the node device is detected and the TE FRR is triggered, and hello packets may be transmitted periodically between RSVP-TE devices to detect the activity of the adjacent devices; if a fault occurs to the paths and the node devices that need protection, the hello packets may not be transmitted normally between adjacent RSVP-TE devices, and then the adjacent devices where the fault occurs may not receive the hello packets; after multiple periods of hello packet (normally 3, the shortest of which is 1 s), it is determined that the fault occurs, and the TE FRR is triggered to switch, and then the traffic is switched to the pre-set standby path. The conventional art, however, takes at least 3 s to detect the fault of the adjacent devices and then trigger the TE FRR switching; as a result, this can not meet the requirement of the real-time services, such as speech, video, etc on the interruption interval; when the path and node devices work normally, and a fault occurs on a forwarding engines, ie on routers, where the fault is caused by a fault on the forwarding engines or internal errors, this fault can not be detected.
In the present disclosure, a method for detecting the path and node faults through a Bidirection Forwarding Detection (BFD) protocol and triggering the TE EFRR is provided. At present, the BFD is applied to types of protocol, including many routing protocols, MPLS TE, etc. The BFD protocol is deployed among the adjacent devices to detect the faults in the paths between the adjacent devices, the node devices, or even the faults on forwarding engines themselves. When the BFD is applied to TE FRR, the BFD protocol is run among the RSVP-TE adjacent devices, and packets are sent periodically. The packets are generated by the forwarding engine, and as a result, under the condition that two devices are connected by a transmission equipment, the BFD may bidirectionally detect the faults in the path at one end, the node device or even the transmission equipment in as short as 30 ms, and then trigger the TE FRR to switch to the standby path, so that the deficiencies of detecting the faults in the path and the node device and triggering the TE FRR by the RSVP-TE signaling protocol may be overcome.
Along with the development of the value-added service of the carriers, the requirement posed by the users and the carriers on the Quality of Service (QoS) is increasingly higher; particularly, after real-time voice and video services transmitted on the conventional IP network, it is common that the carrier and the user sign a Service Level Agreement (SLA). Since the carrier network, especially the massive carrier network, usually undergoes the long-distance transmission path; therefore, the signal attenuation of some extent caused by the path and the transmission equipment themselves is unavoidable. Since many long-distance transmission paths adopt the original transmission paths or paths via the satellite and microwave, the signal quality and the QoS can not be guaranteed, either could the SLA signed by the user be satisfied, thereby degrading the user's experience and the satisfactory degree of the user to the carrier.
In the above solution, although it is guaranteed that the TE FRR is triggered after the fault is detected; when the quality of the signal degrades, for example, when the congestion caused by heavy traffic (especially, burst traffic for wide application of Peer to Peer (P2P), attack on network, equipment virus, etc) occurs in the path of the traffic of the voice and video real-time services, a great deal of packet loss may happen to the traffic of the voice and video real-time service or long delay may occur, thereby seriously degrading the QoS. Under this condition, however, faults do not occur in the path and node that carry the traffic, and in the solution of the prior art, the TE FRR can not triggered; as a result, even though a light-load standby path is deployed in the conventional network, the TE FRR can not be triggered to switch to the standby path, thereby degrading the QoS and causing the waste of the path and bandwidth.